After updating to Windows x64 2101 from 2091, ctrl+alt+up and ctrl+alt+down have no effect.Nothing is printed in the console. Middle-drag still works. My user .sublime-keybinding is empty, and the default still lists them as executing "select_lines".

sublime.log_commands() is saying the command isn't executed, though other operations are logged. I tried restoring "Default\Default (Windows).sublime-keymap" from "Pristine Packages\Default.sublime-package", but it was binary identical, and behaves the same. It contains:

Checking incase another package had overriden it somehow, Find in folder Packages, files *.sublime-keymaps only found mappings for "ctrl+alt+up" in "Default\Default (OSX).sublime-keymap" and "Default\Default (Windows).sublime-keymap" (i'm surprised at the OSX match, but I guess you call option "ctrl" for ease of adding mappings?). I'm stumped!

Ugh. This was due to crappy laptop graphics drivers stealing the ctrl-shift-<arrow> keys for external screen rotation, but for some reason not actually *doing* anything with them. No idea why they kicked in the same time as the ST update, I might have forgotten about a graphics driver update.